Swati Azad and Mridula are two inseparable friends in college. After successfully completing their college, they get married to Ajay Lal and Milind Khanna respectively. Four years later, Prasad Saxena, another former collegian meets with a pregnant Mridula and informs her that Swati has committed suicide as she had lost her sanity. However, he suspects that she was actually killed by the Lal family. Mridula gets hold of Swati’s diary, reads it, and concludes that the Lal family did kill Swati. S...